Led lamp with an inner border and an outer border on light emitting surface

ABSTRACT

An LED lamp includes: a lamp shell including a lamp head, a lamp neck and a sleeve, the lamp head connects to the lamp neck which connects to the sleeve; a passive heat dissipating element having a heat sink connected to the lamp shell, wherein the heat sink comprises fins and a base; a power source; a light emitting surface; a first heat dissipating channel formed in a first chamber of the lamp shell; a second heat dissipating channel formed in the heat sink and between the fins and the base; a lamp cover connected with the heat sink and having a light output surface and an end surface; wherein a third aperture is located in a central region of the light emitting surface, and the third aperture forms an air intake of both the first heat dissipating channel and the second heat dissipating channel; wherein the light emitting surface has an inner border and an outer border encircling the inner border, both the inner border and the outer border separately upward extend along the axial direction of the LED lamp to form a region, an area of part of the fins inside the region is greater than an area of part of the fins outside the region.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 16/267,747 filed on 2019 Feb. 5, which claims priority to thefollowing Chinese Patent Applications No. CN 201810130085.3 filed on2018/02/08, CN 201810479044.5 filed on 2018 May 18, CN 201810523952.Xfiled on 2018 May 28, CN 201810573322.3 filed on 2018 Jun. 6, CN201810634571.9 filed on 2018 Jun. 20, CN 201810763800.7 field on 2018Jul. 12, CN 201810763089.5 filed on 2018 Jul. 12, CN 201810972904.9filed on 2018 Aug. 24, CN 201811172470.0 filed on 2018 Oct. 9, CN201811295618.X filed on 2018 Nov. 1, CN 201811299410.5 filed on 2018Nov. 2, CN 201811347198.5 filed on 2018 Nov. 13, CN 201811378174.6 filedon 2018 Nov. 19, and CN 201811466198.7 filed on 2018 Dec. 3, thedisclosures of which are incorporated herein in their entirety byreference.

FIELD OF THE INVENTION

The invention relates to lighting, particularly to LED lamps with aninner border and an outer border on the light emitting surface.

BACKGROUND OF THE INVENTION

Because LED lamps possess advantages of energy saving, high efficiency,environmental protection and long life, they have been widely adopted inthe lighting field. For LED lamps used as an energy-saving green lightsource, a problem of heat dissipation of high-power LED lamps becomesmore and more important. Overheating will result in attenuation oflighting efficiency. If waste heat from working high-power LED lampscannot be effectively dissipated, then the life of LED lamps will bedirectly negatively affected. As a result, in recent years, solution ofthe problem of heat dissipation of high-power LED lamps is an importantissue for the industry.

OBJECT AND SUMMARY OF THE INVENTION

The LED lamp described in the present disclosure includes an LED (lightemitting diode) lamp including a lamp shell including a lamp head, alamp neck and a sleeve, the lamp head connects to the lamp neck whichconnects to the sleeve; a passive heat dissipating element having a heatsink connected to the lamp shell, wherein the heat sink comprises finsand a base, the sleeve of the lamp shell is located in the heat sink,the lamp neck projects from the heat sink, height of the lamp neck is atleast 80% of height of the heat sink; a power source having a firstportion and a second portion, wherein the first portion of the powersource is disposed in both the lamp neck and the lamp head of the lampshell, and the second portion of the power source is disposed in theheat sink of the passive heat dissipating element; a light emittingsurface connected to the heat sink of the passive heat dissipatingelement and comprising LED chips electrically connected to the powersource, wherein the light emitting surface and the heat sink areconnected to form a heat transferring path from the LED chips to thepassive heat dissipating element; a first heat dissipating channelformed in a first chamber of the lamp shell for dissipating heatgenerated from the power source while the LED lamp is working, and thefirst chamber is located between bottom of the LED lamp and an upperportion of the lamp neck; a second heat dissipating channel formed inthe heat sink and between the fins and the base of the heat sink fordissipating the heat generated from the LED chips and transferred to theheat sink; a lamp cover connected with the heat sink and having a lightoutput surface and an end surface, wherein the end surface is formedwith a vent to allow air flowing from outside of the LED lamp into boththe first heat dissipating channel and the second heat dissipatingchannel through the vent; wherein the first heat dissipating channelcomprises a first end on the light emitting surface to allow air flowingfrom outside of the LED lamp into the first chamber, and a second end onthe upper portion of the lamp neck of the lamp shell to allow airflowing from inside of the first chamber out to the LED lamp; whereinthe second heat dissipating channel comprises a third end on the lightemitting surface to allow air flowing from outside of the LED lamp intothe second heat dissipating channel, and flowing out from spaces betweenevery adjacent two of the fins; wherein a third aperture is located in acentral region of the light emitting surface, and the third apertureforms an air intake of both the first heat dissipating channel and thesecond heat dissipating channel; wherein the light emitting surface hasan inner border and an outer border encircling in the inner border, boththe inner border and the outer border separately upward extend along anaxial direction of the LED lamp to form a region, an area of part of thefins inside the region is greater than an area of part of the finsoutside the region.

Preferably, the base of the heat sink has a lower end located under thebase, the lower end protrudes from the light emitting surface in an axisof the LED lamp; another side of the base of the heat sink, which isopposite to the lower end, has a back side, an end of each of the finsof the heat sink extends to connect with the back side, when the LEDlamp is being hung, in an inward radial direction, the back side isupwardly slanted.

Preferably, the fins of the heat sink include first fins and secondfins, each of the first fins is divided into two portions in a radialdirection of the LED lamp, the two portions are divided with a gapportion, each of the second fins has a third portion and a fourthportion extending therefrom, the fourth portions are located radiallyoutside the third portions, the third portion is connected to the fourthportion through a transition portion, the transition portion has abuffer section and a guide section, a direction of any tangent of theguide section is separate from the gap portion.

Preferably, a receiving space is encompassed by the lower ends forreceiving the lamp cover, height of the lamp cover received in thereceiving space does not project from the lower end.

Preferably, the light emitting surface includes three LED chip sets,each of the three LED sets has LED chips, the light emitting surface isdivided into three areas comprising an inner ring, a middle ring and anouter ring, the three LED chip sets are respectively located in theinner ring, the middle ring and the outer ring, when at least one fin isprojected onto a plane on which the LED chip set is located along theaxial direction of the LED lamp, a projection of the at least one fin atleast touches at least one LED chip of the LED chip set in the innerring, the middle ring or the outer ring.

Preferably, any of the fins is projected onto a plane on which the LEDchip set is located along the axial direction of the LED lamp, aprojection of any of the fins at least touches at least one LED chip ofthe LED chip set.

Preferably, the LED chip set in the outer ring corresponding to the finsare greater than the LED chip set in the inner ring in number, the LEDchip set in the outer ring has more LED chips than the LED chip set inthe inner ring in number.

Preferably, the sleeve corresponds to the third aperture.

Preferably, each LED chip of one of the LED chip sets on the lightemitting surface is radially interlacedly arranged with any one LED chipof adjacent one of the LED chip sets on the light emitting surface.

Preferably, the projecting area of the gap portion directly exactlycorresponds to an area that the LED chips are positioned on the lightemitting surface.

Preferably, the first air inlet is projected onto the end surface in anaxis of the LED lamp to occupy an area on the end surface, which isdefined as a first portion, another area on the end surface is definedas a second portion, and the vent in the first portion is greater thanthe vent in the second portion in area.

Preferably, an inner reflecting surface is disposed inside the lightoutput surface of the lamp cover, an outer reflecting surface isdisposed in outer circle of the array of LED chips.

Preferably, a second chamber is formed between the light output surface,the inner reflecting surface, the outer reflecting surface and the lightemitting surface, the LED chips of the light emitting surface arelocated in the second chamber.

Preferably, the second chamber has first apertures and second apertures,the first apertures are configured to communicate with the outside, andthe second apertures are configured to communicate simultaneously withboth the first heat dissipating channel and the second heat dissipatingchannel.

Preferably, the light output surface is provided with holes to form thefirst apertures, the first apertures are annularly located at acircumferential portion of the light output surface.

Preferably, the inner reflecting surface is provided with notches toform the second apertures, the second apertures are annularly located ata circumferential portion of the inner reflecting surface.

Preferably, the ratio of the number of the second apertures to that ofthe first apertures is about 1:1-2.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed descriptions, given by way of example, and notintended to limit the present invention solely thereto, will be best beunderstood in conjunction with the accompanying figures:

FIG. 1 is a structural schematic view of one embodiment of an LED lampaccording to aspects of the invention;

FIG. 2 is a schematic cross-sectional view of the LED lamp of FIG. 1;

FIG. 3 is an exploded view of the LED lamp of FIG. 1;

FIG. 4 is a schematic cross-sectional view of the LED lamp of FIG. 1,which shows the first heat dissipating channel and the second heatdissipating channel;

FIG. 5 is a perspective view of the LED lamp of FIG. 1;

FIG. 6 is a structural schematic view of FIG. 5 without the light outputsurface;

FIG. 7 is a perspective view of another embodiment of an LED lampaccording to aspects of the invention;

FIG. 8 is a schematic view of FIG. 7 without the light output surface;

FIG. 9 is a schematic view of an end surface of the lamp cover of anembodiment;

FIG. 10 is a schematic view of an end surface of the lamp cover,according to another embodiment of the present invention;

FIG. 11 is another view of the end surface of FIG. 10;

FIGS. 12A-12G are schematic views of some embodiments of the lamp cover,

FIG. 13 is a perspective view of an LED lamp, according to anotherembodiment of the present invention;

FIG. 14 is a cross-sectional view of the LED lamp of FIG. 13;

FIG. 15 is a top view of the heat sink of the LED lamp of FIG. 13;

FIG. 16 is an enlarged view of portion E in FIG. 15;

FIG. 17 is a schematic view showing a vortex formed by air near thesecond fins according to another embodiment of the present invention;

FIG. 18 is a bottom view of the LED lamp of FIG. 1 without the lampcover;

FIG. 19 is an enlarged view of portion A in FIG. 18;

FIG. 20 is a schematic view of the combination of the fins and the LEDchips of an embodiment;

FIG. 21 is a schematic view of the combination of the fins and the LEDchips, according to some embodiments of the present invention;

FIG. 22 is a schematic view of an embodiment of the light board;

FIG. 23 is a schematic view of another embodiment of the light board;

FIGS. 24A-24C are perspective views of the power source, according tosome embodiments of the present invention;

FIG. 24D is a main view of the power source of the embodiment of FIGS.24A-24C;

FIG. 25 is a cross-sectional view of the LED lamp of another embodiment;

FIG. 26 is a schematic view of an arrangement of the convection channelsof the LED lamp of FIG. 25.

DETAILED DESCRIPTION OF THE EMBODIMENTS

To make the present invention understandable and readable, the followingdisclosure will now be described in the following embodiments withreference to the drawings. The following descriptions of variousembodiments of this invention are presented herein for purpose ofillustration and giving examples only.

FIG. 1 is a structural schematic view of an embodiment of an LED lampaccording to certain aspects of the invention. FIG. 2 is a schematiccross-sectional view of the LED lamp of FIG. 1. FIG. 3 is an explodedview of the LED lamp of FIG. 1. As shown in the figures, the LED lampincludes a heat sink 1, a lamp shell 2, a light board 3, a lamp cover 4and a power source 5. In this embodiment, the light board 3 is connectedto the heat sink 1 by attachment for rapidly transferring heat from thelight board 3 to the heat sink 1 when the LED lamp is working. In someembodiments, the light board 3 is riveted to the heat sink 1. In someembodiments, the light board 3 is screwed to the heat sink 1. In someembodiments, the light board 3 is welded to the heat sink 1. In someembodiments, the light board 3 is adhered to the heat sink 1. In thisembodiment, the lamp shell 2 is connected to the heat sink 1, the lampcover 4 covers the light board 3 to make light emitted from the lightboard 3 pass through the lamp cover to project out. The power source 5is located in a chamber of the lamp shell 2 and the power source 5 is ECto the LED chips 311 for providing electricity.

FIG. 4 is a schematic cross-sectional view of the LED lamp. As shown inFIGS. 2 and 4, the chamber of the lamp shell 2 of this embodiment isformed with a first heat dissipating channel 7 a. An end of the firstheat dissipating channel is formed with a first air inlet 2201. Anopposite end of the lamp shell 2 is formed with a venting hole 222 (atan upper portion of the lamp neck 22). Air flows into the first heatdissipating channel 2201 and flows out from the venting hole 222 forbringing out heat in the first heat dissipating channel 7 a (primarily,heat of the working power source 5). As for the path of heatdissipation, heat generated from the heat-generating components of theworking power source 5 is transferred to air (around the heat-generatingcomponents) in the first heat dissipating channel 7 a by thermalradiation first, and then external air enters the first heat dissipatingchannel 7 a by convection to bring out internal air to make heatdissipation. In this embodiment, the venting hole 222 at the lamp neck22 can also make direct heat dissipation.

As shown in FIGS. 1, 2 and 4, a second heat dissipating channel 7 b isformed in the fins and the base 13 of the heat sink 1. The second heatdissipating channel 7 b has a second air inlet 1301. In this embodiment,the first air inlet 2201 and the second air inlet 1301 share the sameopening formed on the light board 3. This will be described in moredetail later. Air flows from outside of the LED lamp into the second airinlet 1301, passes through the second heat dissipating channel 7 b andfinally flows out from spaces between the fins 11 so as to bring outheat of the fins 11 to enhance heat dissipation of the fins 11. As forthe path of heat dissipation, heat generated from the LED chips isconducted to the heat sink 1, the fins 11 of the heat sink 1 radiate theheat to surrounding air, and convection is performed in the second heatdissipating channel 7 b to bring out heated air in the heat sink 1 tomake heat dissipation.

FIG. 5 is a perspective view of the LED lamp of an embodiment, whichshows assembling of the heat sink 1 and the lamp cover 4. FIG. 6 is astructural schematic view of FIG. 5 without the light output surface 43.As shown in FIGS. 5 and 6, in this embodiment, the lamp cover 4 includesa light output surface 43 and an end surface 44 with a vent 41. Airflows into both the first heat dissipating channel 7 a and the secondheat dissipating channel 7 b through the vent 41. When the LED chips 311(shown in FIG. 6) are illuminated, the light passes through the lightoutput surface 43 to be projected from the lamp cover 4. In thisembodiment, the light output surface 43 may use currently availablelight-permeable material such as glass, PC, etc. The term “LED chip”mentioned in all embodiments of the invention means all light sourceswith one or more LEDs (light emitting diodes) as a main part, andincludes but is not limited to an LED bead, an LED strip or an LEDfilament. Thus, the LED chip mentioned herein may be equivalent to anLED bead, an LED strip or an LED filament.

As shown in FIGS. 5 and 6, in this embodiment, an inner reflectingsurface 4301 is disposed inside the light output surface 43 of the lampcover 4. The inner reflecting surface 4301 is disposed in the innercircle of the array of LED chips 311. In an embodiment, an outerreflecting surface 4302 is disposed in the outer circle of the array ofLED chips 311. The outer reflecting surface 4302 corresponds to the LEDchips 311 on the light board 3. The arrangement of both the innerreflecting surface 4301 and the outer reflecting surface 4302 is usedfor adjusting a light emitting range of the LED chip set 31 to make thelight concentrated and to increase brightness in a local area. Forexample, under the condition of the same luminous flux, illuminance ofthe LED lamp can be increased. In one example, all the LED chips 311 inthis embodiment are mounted on the bottom side of the light board 3 (ina using status). In this embodiment, the LED lamp of the presentembodiment does not emit lateral light from the LED chips 311. Whenworking, the primary light emitting surfaces of the LED chips 311 arecompletely downward. At least 60% of the light from the LED chips 311are emitted through the light output surface 43 without reflection. As aresult, in comparison with those LED lamps with lateral light (thelateral light is reflected by a cover or a lampshade to be emitteddownward, and in theory there must be part of light loss in the processof reflection.) The LED chips 311 in this embodiment possess betterlight emitting efficiency. In one example, under the condition of thesame lumen value (luminous flux), the LED lamp in the present embodimentpossesses higher illuminance. And the emitted light can be concentratedto increase illuminance in a local area by the arrangement of both theinner reflecting surface 4301 and the outer reflecting surface 4302, forexample, in an area under the LED lamp between 120 degrees and 130degrees (a light emitting range under the LED lamp between 120 degreesand 130 degrees). When the LED lamp is installed at a relatively highposition, in the same angular range of light emitting, the lit area ofthe LED lamp still satisfies the requirement and illuminance in thisarea can be higher.

The inner reflecting surface 4301 is used for reflecting part of lightemitted from the innermost LED chips 311 of the LED chip set 31. Theouter reflecting surface 4302 is used for reflecting part of lightemitted from the outermost LED chips of the LED chipset 31. Theoutermost LED chips 311 are greater than the innermost LED chips 311 innumber. The outer reflecting surface 4302 is greater than the innerreflecting surface 4301 in area. Because the outermost portion of theLED chip set 31 includes more LED chips than the innermost portion,larger reflecting area is beneficial to regulate light output.

In this embodiment, the inner reflecting surface 4301 and the outerreflecting surface 4302 have first area A1 and second area A2,respectively. The LED chips 311 in the outermost portion of the LED chipset 31 and in the innermost portion of the LED chip set 31 are N1 and N2in number, respectively. Their relationship is:

(A1/N1):(A2/N2)=0.4˜1

When the ratio of area of the inner reflecting surface 4301corresponding to a single LED chip 311 in the innermost portion of theLED chip set 31 to area of the outer reflecting surface 4302corresponding to a single LED chip 311 in the outermost portion of theLED chip set 31 falls in the above range, both the LED chips 311 in theinnermost portion of the LED chip set 31 and the LED chips 311 in theoutermost portion of the LED chip set 31 have a better effect of lightoutput.

As show in FIGS. 5 and 6, in this embodiment, in order to prevent dustfrom covering on the LED chips 311 to reduce light efficiency of the LEDchips or affect heat dissipation of the LED chips 311, the LED chips 311may be received in a sealed room. For example, a sealed chamber 9 isformed between the light output surface 43, the inner reflecting surface4301, the outer reflecting surface 4302 and the light board 3 (this term“sealed” mentioned here may mean “without obvious pores”, not includingunavoidable gaps in an assembling process). In some embodiments, whenomitting both the inner and outer reflecting surfaces 4301, 4302, thesealed chamber 9 is formed between the light output surface 43 and thelight board 3 or between the light output surface 43, the heat sink 1and the light board 3.

FIG. 7 is a perspective view of another embodiment of the LED lamp ofthe invention. It differs from the above embodiment by holes formed inthe chamber 9. FIG. 8 is a schematic view of FIG. 7 without the lightoutput surface 43. As shown in FIGS. 7 and 8, in some embodiments, achamber 9 is formed between the light cover 4 and the light board 3. Indetail, the chamber 9 is formed between the light output surface 43, theinner reflecting surface 4301, the outer reflecting surface 4302 and thelight board 3 and the LED chips of the light board 3 are located in thechamber 9. The chamber 9 has first apertures 91 and second apertures 92.The first apertures 91 are configured to communicate with the outside,and the second apertures 92 are configured to communicate simultaneouslywith both the first heat dissipating channel 7 a and the second heatdissipating channel 7 b. In an aspect of heat dissipation, airconvection is formed in the chamber 9 to bring out part of heatgenerated from the LED chips 311, and outside air flows into the LEDlamp through the chamber 9 so as to enhance convection in both the firstheat dissipating channel 7 a and the second heat dissipating channel 7b. In some embodiments, both the inner and outer reflecting surfaces4301, 4302 may be omitted. In one example, a chamber 9 is formed betweenthe light output surface 43 and the light board 3.

As shown in FIG. 7, in some embodiments, the light output surface 43 isprovided with a hole to form the first apertures 91. Preferably, thefirst apertures 91 are annularly located at a circumferential portion ofthe light output surface 43 to make it not affect the effect of lightpenetration of the light output surface 43. In an aspect of structure,the light output surface 43 may be thermally deformed while the LED lampis working. The first apertures 91 makes the light output surface 43have a deformable space to prevent the light output surface 43 frombeing deformed to press the heat sink and cause damage of the lightoutput surface 43. In this embodiment, the first apertures 91 areannularly located at a circumferential portion of the light outputsurface 43. As a result, air convection can be enhanced and structuralstrength of the light output surface 43 heated can also be reinforced.

As shown in FIG. 8, in some embodiments, the inner reflecting surface4301 is provided with notches to form the second apertures 92. In thisembodiment, the second apertures 92 are annularly located at acircumferential portion of the inner reflecting surface 4301. The ratioof the number of the second apertures 92 to that of the first apertures91 is about 1:1-2, preferably, 1:1.5. Thus, air intake and outtake canbe balanced. In other embodiments, both the first apertures 91 and thesecond apertures 92 may also be formed at other portions of the lampcover 4 such as the light board 3 or the base 13 of the heat sink 1.

As shown in FIGS. 7 and 8, in some embodiments, a chamber 9 is formedbetween the light cover 4 and the light board 3. In detail, the chamber9 is formed between the light output surface 43, the inner reflectingsurface 4301, the outer reflecting surface 4302 and the light board 3and the LED chips 311 of the light board 3 are located in the chamber 9.The chamber 9 has pressure release apertures to prevent temperature andpressure in the chamber from being raised by the working LED chips 311.The pressure release aperture may be the first apertures 91 of the lightoutput surface 43, the second apertures 92 of the inner reflectingsurface 4301, or holes at the heat sink 1 or the light board 3, whichcommunicate with the chamber 9.

FIG. 9 is a schematic view of an end surface 44 of the lamp cover 4 ofan embodiment. As shown, the ratio of a total of cross-sectional area ofthe vent 41 to overall area of the end surface 44 (area of a single sideof the end surface 44, such as the side away from the LED chips 311) is0.01-0.7. Preferably, the ratio of a total of cross-sectional area ofthe vent 41 to overall area of the end surface 44 is 0.3-0.6. Morepreferably, the ratio of a total of cross-sectional area of the vent 41to overall area of the end surface 44 is 0.4-0.55. By limiting the ratioof a total of cross-sectional of the vent 41 to overall area of the endsurface 44 to the above ranges, not only can air intake of the vent 41be guaranteed, but also adjustment of area of the vent 41 is implementedunder ensuring structural strength of the end surface 44. When the ratioof area of the vent 41 to area of the end surface 44 is 0.4-0.55, notonly can air intake of the vent 41 be guaranteed to satisfy requirementsof heat dissipation of the LED lamp, but also the vent 41 does notaffect structural strength of the end surface 44 to prevent the endsurface 44 with the vent 41 from being fragile due to collision orpressure.

FIG. 10 is a schematic view of an end surface 44 of the lamp cover 4 ofanother embodiment. As shown in FIGS. 10 and 11, a periphery of the vent41 has an enlarged thickness to form rib portions 411. An air guideopening 412 in a direction of air intake of the vent 41 is formedbetween adjacent two of the rib portions 411. A periphery of the vent 41with an enlarged thickness can enhance structural strength of the endsurface 44 to avoid reduction of overall structural strength due to thevent 41. On the other hand, the air guide opening 412 has an effect ofair guiding to make air flowing into the air guide opening 412 have aspecific direction. In addition, when the end surface 44 is beingformed, the rib potions 411 avoid reduction of overall structuralstrength of the end surface 44. Thus, the end surface 44 is hard to bedeformed because of the vent 41 to increase the yield rate ofmanufacture. In this embodiment, the rib portions 411 are formed on theside of the end surface 44, which is adjacent to the light board.

As shown in FIG. 11, the thickness of periphery of the vent 41 isgreater than that of other portions of the end surface 44 so as toimprove strength of the parts around the vent 41 and the effect of airguiding.

As shown in FIG. 9, a diameter of a maximum inscribed circle of the vent41 is less than 2 mm, preferably, 1.0-1.9.mm. As a result, both bugs andmost dust can be resisted, and venting efficiency of the vent 41 can bekept great enough. In one example, alternatively, the vent 41 definesboth a length direction and a width direction, i.e. the vent has alength and a width, and the length is greater than the width. Thelargest width of inscribed circle of the vent 41 may be less than 2 mm.In an embodiment, the largest width is from 1 mm to 1.9 mm. In addition,the largest width of the vent 41 may be greater than 1 mm. If the widthof the vent 41 is less than 1 mm, then more pressure is required to pushair to enter the vent 41, which is advanced for venting.

FIGS. 12A-12G show shapes of some embodiments of the vent 41. As shownin FIGS. 12A-12G, the vent 41 may be circular, strip-shaped, arced,trapezoidal, diamond or their combination. As shown in FIG. 12A, whenthe vent 41 is configured to be circular, its diameter should be lessthan 2 mm to resist bugs and most dust and venting efficiency of thevent 41 can be kept great enough. As shown in FIGS. 12B and 12C, whenthe vent 41 is configured to be strip-shaped or arced, its width shouldbe less than 2 mm to accomplish the above effects. As shown in FIG. 12D,when the vent 41 is configured to be trapezoidal, its lower base shouldbe less than 2 mm to accomplish the above effects. As shown in FIG. 12E,when the vent 41 is configured to be round-cornered rectangular, itswidth should be less than 2 mm to accomplish the above effects. As shownin FIGS. 12F and 12G, when the vent 41 is configured to be triangular ordrop-shaped, a diameter of its maximum inscribed circle should be lessthan 2 mm.

In some embodiments, the vent 41 on the end surface 44 is multiple innumber. For example, the vents 41 may be annularly arranged on the endsurface 44 for even air intake. The vents 41 may also be radiallyarranged on the end surface 44. The vents 41 may also be irregularlyarranged.

In FIG. 12A, there are two broken lines on the end surface 44. The innerbroken line represents a position the first air inlet 2201 (as shown inFIG. 2) is projected onto the end surface 44. The region within theinner broken line is defined as a first portion (first opening region433). The region between the inner circle and the outer circle isdefined as a second portion (second opening region 434). In thisembodiment, the first air inlet 2201 is projected onto the end surfacein an axis of the LED lamp to occupy an area on the end surface 44, itis the first portion (first opening region 433). The other area on theend surface 44 is the second portion (second opening region 434). Thevent 41 in the first portion is greater than the vent 41 in the secondportion in area. Such an arrangement is advantageous to making most airflow into the first heat dissipating channel 7 a for better effect ofheat dissipation to the power source 5 and reduction of rapidly aging ofelectronic components of the power source 5. These features are alsoavailable to the vent 41 in other embodiments.

In other embodiments, the first air inlet 2201 is projected onto the endsurface 44 in an axis of the LED lamp to occupy an area on the endsurface 44, which may be a first portion (first opening region 433). Theother area on the end surface 44 may be a second portion (second openingregion 434). The vent 41 in the first portion is greater smaller thanthe vent 41 in the second portion in area. As a result, heat of the fins11 can be better dissipated to perform better heat dissipation to theLED chips 311 and prevent a region around the LED chips 311 from forminghigh temperature. In detail, area of both the first portion and thesecond portion can be selected according to actual requirements.

In some applications, there may be a limit of overall weight of an LEDlamp. For example, when an LED lamp adopts an E39 head, its maximumweight limit is 1.7 Kg. Thus, besides the fundamental elements such as apower source, a lamp cover and a lamp shell, in some embodiments, weightof a heat sink is limited within 1.2 Kg. For some high-power LED lamps,the power is about 150 W-300 W, and their luminous flux can reach 20000lumens to 45000 lumens. Under a limit of weight, a heat sink shoulddissipate heat from an LED lamp with 20000-45000 lumens. Under acondition of heat dissipation of natural convection, usually power of 1W needs area of heat dissipation of at least 35 square cm. The followingembodiments intend to reduce area of heat dissipation for power of 1 Wunder guarantee of a receiving space of the power source 5 and effect ofheat dissipation. Under a precondition of weight limit of the heat sink1 and limit of the power source 5, the best effect of heat dissipationcan be accomplished.

As shown in FIGS. 1 and 2, in this embodiment, the LED lamp includespassive heat dissipating elements which adopt natural convection andradiation as a heat dissipating manner without any active heatdissipating elements such as a fan. The passive heat dissipating elementin this embodiment includes a heat sink 1 composed of fins 11 and a base13. The fins 11 radially extend from and connect to the base 13. Whenusing the LED lamp, at least part of heat from the LED chips 311 isconducted to the heat sink 1 by thermal conduction. At least part ofheat occurring from the heat sink 1 is transferred to external air bythermal convection and radiation.

A diameter of a radial outline of the heat sink 1, in a hanging statusas shown in the figures, tapers off upward or is substantially in ataper shape for a better match with a lampshade. When the heat sink 1 inthis embodiment is dissipating heat, at least part of heat is thermallyradiated to air therearound to perform heat dissipation. An importantfactor of thermal radiation is emissivity. To improve emissivity of theheat sink 1, surfaces of the heat sink in this embodiment are speciallytreated. For example, surfaces of the heat sink 1 are provided withradiation heat-dissipating paint or electrophoretic coating to increaseefficiency of thermal radiation and to rapidly dissipate heat of theheat sink 1. Another solution is forming a nanostructured porous aluminalayer on the surfaces of the fins 11 by anodization in an electrolyte toform a layer of nanostructured porous alumina. As a result, ability ofheat dissipation of the fins 11 can be enhanced without adding thenumber of the fins 11. Alternatively, the surfaces of the fins 11 may becoated with an anti-thermal-radiation layer to reduce thermal radiationbetween the fins 11. This can make more heat radiate to air. Theanti-thermal-radiation layer may adopt paint or oxide coating, in whichthe paint may be normal paint or radiation heat dissipation paint. Tofurther enhance heat dissipating effect of the heat sink 1. As shown inFIGS. 2, 4 and 5, the base 13 of the heat sink 1 has a lower end 133located under the base 13, i.e. both the lower end 133 and the lightboard 3 are located on the same side. In this embodiment, the lower end133 protrudes from the light board 3 in an axis of the LED lamp. In ausing (hanging) status of the light board 3 being downward, the lowerend 133 is lower than the light board 3 in position. As a result, theposition of the lower end 133 can protect the LED board 3. Whencollision occurs, the lower end 133 will collide first to prevent thelight board 3 from colliding. As shown in FIGS. 2 and 4, in anotheraspect, the base 13 has a recess 132 in which the light board 3 isplaced. The recess 132 is of a cylindrical shape or a substantiallycylindrical shape, or a cylindrical platform structure. When the recess132 is of a cylindrical shape, a diameter of the cylinder is less thanthat of the base 13. The recess 132 in the base 13 is advantageous toreducing a glare effect of the LED lamp and improve direct vision andcomfort of users (inner walls of the recess 132 screen at least part oflateral light from the LED chips 311 to decrease glare). In someembodiments, the base 13 may have no recess. In some embodiments, tomake both the light board 3 and the heat sink 1 have maximum contactarea to guarantee a heat dissipation effect, a surface of the base 13 isa flat plane.

FIG. 13 is a perspective view of an LED lamp of an embodiment of thepresent invention. As shown in FIGS. 2 and 13, another side of the base13 of the heat sink 1, which is opposite to the lower end 133, has aback side 134. An end of each fin 11 extends to connect with the backside 134. Thus, At least part of each fin 11 projects from the LED lightboard 3 in an axis. In one example, in an axial direction of the LEDlamp, each of the fins 11 is formed with an extension portion 1101between the back side 134 of the base 13 and the light board 3. Theextension portions 1101 can increase area of heat dissipation of thefins 11 and improve an effect of heat dissipation. In addition, theextension portion 1101 does not increase overall height of the LED lampso as to be advantageous to controlling overall height of the LED lamp.

FIG. 14 is a cross-sectional view of the LED lamp of this embodiment. Asshown, in this embodiment, the back side 134 of the base 13 is slanted.For example, when the LED lamp is being hung, in an inward radialdirection, the back side 134 is upwardly slanted. In another aspect, ina radial direction of the LED lamp toward an axis of the LED lamp, anaxial distance from the back side 134 to the light board 3 isprogressively increased. Such an arrangement is advantageous toconvection air is introduced along the back side 134 to bring out heatof the back side 134 and prevents the back side 134 from obstructing airflowing into.

As shown in FIGS. 2 and 5, in a using status, the light board 3 isdownwardly arranged, a position of the lower end 133 is lower than anend side 44 of the lamp cover 4 and the light output surface 43. As aresult, when packing, transporting or using the LED lamp, if collisionoccurs, then the lower end 133 will collide to prevent the lamp coverfrom colliding to damage the end side 44 or the light output surface 43.

As shown in FIGS. 2 and 5, a receiving space (indent 132) is encompassedby the lower ends 133 for receiving the lamp cover 4. Height of the lampcover 4 received in the receiving space does not project from the lowerend 133. Height of the LED lamp mainly includes height of the lamp shell2, height of the heat sink 1 and height of the lamp cover 4. In thisembodiment, the lamp cover 4 does not project from the lower end 133,this can control overall height of the lamp and the lamp cover 4 doesnot increase overall height of the lamp. In another aspect, the heatsink 1 additionally increases heat dissipating portion (downwardprotruding part of the light board 3 corresponding to the lower end133). In other embodiments, a part of the lamp cover 4 may project fromthe lower end 133.

As shown in FIGS. 2,4 and 5, a gap is kept between the end side 44 andthe light board 3 to form a room 8. The room 8 communicates with boththe first air inlet 2201 of the first heat dissipating channel 7 a andthe second air inlet 1301 of the second heat dissipating channel 7 b.Air flows into the room 8 through the vent 41 of the end side 44 andthen flows into both the first heat dissipating channel 7 a and thesecond heat dissipating channel 7 b. The room 8 allows air therein tomix and the mixed air is distributed according to negative pressure(resulting from temperature difference) of both the first and secondheat dissipating channels 7 a, 7 b so as to make distribution of airmore reasonable.

In this embodiment, when a passive heat dissipation manner (fanless) isadopted, the ratio of power (W) of the LED lamp to heat dissipatingsurface area (square cm) of the heat sink 1 is 1:20-30. That is, eachwatt needs heat dissipating surface area of 20-30 square cm for heatdissipation. Preferably, the ratio of power of the LED lamp to heatdissipating surface area of the heat sink 1 is 1:22-26. More preferably,the ratio of power of the LED lamp to heat dissipating surface area ofthe heat sink 1 is 1:25. The first heat dissipating channel 7 a isformed in the lamp shell 2, the first heat dissipating channel 7 a hasthe first air inlet 2201 at an end of the lamp shell 2, and another endof the lamp shell 2 has the venting hole 222. Air flows into the firstair inlet 2201 and flows out from the venting hole 222 to bring out heatin the first heat dissipating channel 7 a. The second heat dissipatingchannel 7 b is formed in the fins 11 and the base 13 and the second heatdissipating channel 7 b has the second air inlet 1301. Air flows intothe second air inlet 1301, passes the second heat dissipating channel 7b, and finally flows out from the spaces between the fins 11 to bringout heat radiated from the fins 11 to air therearound and enhance heatdissipation of the fins 11. By both the first and second heatdissipating channels 7 a, 7 b, efficiency of natural convection can beincreased. This reduces required area of heat dissipation of the heatsink 1 so as to make the ratio of power of the LED lamp to heatdissipating area of the heat sink 1 be between 20 and 30. In thisembodiment, overall weight of the LED lamp is less than 1.7 Kg. When theLED lamp is provided with power of about 200 W (below 300 W, preferably,below 250 W), the LED chips 311 are lit up and emit luminous flux of atleast 25000 lumens.

As shown in FIG. 1, weight of the heat sink 1 in this embodimentaccounts for above 50% of weight of the LED lamp. In some embodiments,weight of the heat sink 1 accounts for 55-65% of weight of the LED lamp.Under this condition, volume of the heat sink 1 accounts for above 20%of volume of the overall LED lamp. Under a condition of the same thermalconductivity of the heat sink 1 (i.e. overall heat sink 1 uses a singlematerial or two different materials with almost identical thermalconductivity), the larger the volume occupied by the heat sink 1 is, thelarger the heat dissipating area which can be provided by the heat sink1 is. As a result, when volume of the heat sink 1 accounts for above 20%of volume of the overall LED lamp, the heat sink 1 may have more usablespace to increase its heat dissipating area. Considering the arrangementspace of the power source 5, the lamp cover 4 and the lamp shell 2,preferably, volume of the heat sink 1 accounts for 20%-60% of volume ofthe overall LED lamp. More preferably, volume of the heat sink 1accounts for above 25-50% of volume of the overall LED lamp.Accordingly, although the overall size of the LED lamp is limited andthe space for receiving the power source 5, the lamp cover 4 and thelamp shell 2 must be kept, volume of the heat sink 1 can still bemaximized. This is advantageous to design of overall heat dissipation ofthe LED lamp.

FIG. 15 is top view of the heat sink 1 of the LED lamp of an embodiment.As shown, the heat sink 1 suffers the above volume limit, so at leastpart of the fins 11 are extended outward in a radial direction of theLED lamp with at least two sheets at an interval. By such anarrangement, the fins 11 in a fixed space can have larger area of heatdissipation. In addition, the extended sheets form support to the fins11 to make the fins firmly supported on the base 13 to prevent the fins11 from deflecting.

In detail, as shown in FIG. 15, the fins include first fins 111 andsecond fins 112. The bottoms of both the first fins 111 and the secondfins 112 in an axis of the LED lamp connect to the base 13. The firstfins 111 interlace with the second fins 112 at regular intervals. Beingprojected from the axial direction of the LED lamp, each of the secondfins 112 is to be seen as a Y-shape. Such Y-shaped second fins 112 canhave more heat dissipating area under a condition of the heat sink 1occupying the same volume. In this embodiment, both the first fins 111and the second fins are evenly distributed on a circumference,respectively. Every adjacent two of the second fins 112 are symmetricalabout one of the first fins 111. In this embodiment, an interval betweenone of the first fins 111 and adjacent one of the second fins 112 is8-12 mm. In general, to make air flow in the heat sink 1 smooth and tomake the heat sink perform a maximum effect of heat dissipation,intervals between the fins 11 should be as uniform as possible.

As shown in FIGS. 8 and 15, at least one of the fins 11 is divided intotwo portions in a radial direction of the LED lamp. Thus, a gap betweenthe two portions forms a passage to allow air to pass. In addition, theprojecting area of the gap directly exactly corresponds to an area thatthe LED chips 311 are positioned on the LED board 3 to enhanceconvection and improve an effect of heat dissipation to the LED chips311. In an aspect of limited overall weight of the LED lamp, part of thefins 11 divided with a gap reduces the amount of the fins 11, decreasesoverall weight of the heat sink 1, and provides a surplus space toaccommodate other elements.

FIG. 16 is an enlarged view of portion E in FIG. 15. As shown in FIGS.15 and 16, the fins 11 includes first fins 111 and second fins 112. Eachof the first fins 11 is divided into two portions in a radial directionof the LED lamp, i.e. a first portion 111 a and a second portion 111 b.The two portions are divided with a gap portion 111 c. The first portion111 a is located inside the second portion 111 b in a radial direction.Each of the second fins 112 has a third portion 112 a and a fourthportion 112 b extending therefrom. The fourth portions 112 b are locatedradially outside the third portions 112 a to increase space utilizationand make the fins have more heat dissipating are for heat dissipation.As shown in FIG. 16, the third portion 112 a is connected to the fourthportion 112 b through a transition portion 113. The transition portion113 has a buffer section 113 a and a guide section 113 b. At least oneor both of the buffer section 113 a and the guide section 113 b arearced in shape. In other embodiment, both the buffer section 113 a andthe guide section 113 b are formed into an S-shape or an invertedS-shape. The buffer section 113 a is configured to prevent air radiallyoutward flowing along the second fins 112 from being obstructed to causevortexes. Instead, the guide section 113 b is configured to be able toguide convection air to radially outward flow along the second fins 112without interference (as shown id FIG. 17).

As shown in FIG. 16, one of the second fins 112 includes a third portion112 a and two fourth portions 112 b. The two fourth portions 112 b aresymmetrical about the third portion 112 a. In other embodiments, one ofthe second fins 112 may include a third portion 112 a and multiplefourth portions 112 b such as three or four fourth portions 112 b (notshown). The multiple fourth portions 112 b of the second fin 112 arelocated between two first fins 111.

As shown in FIG. 16, a direction of any tangent of the guide section 113b is separate from the gap portion 111 c to prevent convection air fromflowing into the gap portion 111 c through the guide portion 113 b, suchthat the poor efficiency of heat dissipation caused by longer convectionpaths is able to be avoid as well. Preferably, a direction of anytangent of the guide section 113 b is located radially outside the gapportion 111 c. In other embodiments, a direction of any tangent of theguide section 113 b is located radially inside the gap portion 111 c.

As shown in FIG. 13, at least partially of fin 11 has a protrusion 1102projecting from a surface of the fin 11. The protrusions 1102 extendalong an axis of the LED lamp and are in contact with the base 13. Asurface of the protrusion 1102 may selectively adopt a cylindrical shapeor a regular or an irregular polygonal cylinder. The protrusions 1102increase surface area of the fins 11 to enhance efficiency of heatdissipation. In addition, the protrusions 1102 also form a supporteffect to the fins 11 to prevent the fins 11 from being inflected inmanufacture. In some embodiments, a single fin 11 is divided into twoportions in a radial direction of the LED lamp. Each portion is providedwith at least one protrusion 1102 to support the two portions. In thisembodiment, the protrusion 1102 is located at an end portion of each fin11 in a radial direction of the LED lamp, for example, at end portionsof the first portions 111 a, 111 b (the ends near the gap portion 111c).

In some embodiments, when each fin 11 is a single piece without the gapportion, the protrusion 1102 may also be disposed on a surface of eachfin 11 (not shown) to increase surface area of heat dissipation of thefins 11 and have a support effect to the fins 11 to prevent the fins 11from being inflected in manufacture.

FIG. 18 is a bottom view of the LED lamp of FIG. 1 without the lampcover 4. FIG. 19 is an enlarged view of portion A in FIG. 18. As shownin FIGS. 18 and 19, the heat sink 1 is disposed outwardly of the sleeve21, and the power source 5 is disposed in the inner space of the sleeve21. A distance is kept between distal ends of the fins 11 and the sleeve21. Accordingly, the sleeve 21 which has been heated to be thermallyexpanded will not be pressed by the fins 11 to be damaged. Also, heatfrom the fins 11 will not be directly conducted to the sleeve 21 toadversely affect electronic components of the power source 5 in thesleeve 21. Finally, air existing in the distance between the fins 11 andthe sleeve 21 of the lamp shell 2 (as shown in FIG. 3) possesses aneffect of thermal isolation so as to further prevent heat of the heatsink 1 from affecting the power source 5 in the sleeve 21. In otherembodiments, to make the fins 11 have radial support to the sleeve 21,distal ends of the fins 11 may be in contact with an outer surface ofthe sleeve 21 and another part of the fins 11 are not in contact withthe sleeve 21. Such a design may be applied in the LED lamp shown inFIG. 18. As shown in FIG. 18, the light board 3 includes a thirdaperture 32 for exposing both the first air inlet 2201 of the first heatdissipating channel 7 a and the second air inlet 1301 of the second heatdissipating channel 7 b. In some embodiments, to rapidly dissipate heatfrom the power source 5, the ratio of cross-sectional area of the firstair inlet 2201 to cross-sectional area of the second air inlet 1301 isgreater than 1 but less than or equal to 2. In some embodiments, torapidly dissipate heat from the power source 5, the ratio ofcross-sectional area of the second air inlet 1301 to cross-sectionalarea of the first air inlet 2201 is greater than 1 but less than orequal to 1.5.

As shown in FIGS. 13 and 14, the innermost of the fins 11 in a radialdirection of the LED lamp is located outside the venting hole 222 in aradial direction of the LED lamp. In one example, an interval is keptbetween the innermost of the fins 11 in a radial direction of the LEDlamp and the venting hole 222 in a radial direction of the LED lamp. Asa result, heat from the fins 11 flowing upward will not gather to theventing hole 222 to keep an interval with the venting hole 222. Thisavoids heat making air around the venting hole 222 heat up to affectconvection temperature speed of the first heat dissipating channel 7 a(the convection speed depends upon a temperature difference between twosides of the first heat dissipating channel 7 a, when air temperaturenear the venting hole 222 rises, the convection speed willcorrespondingly slowdown.).

LEDs generates heat while they are emitting. A key parameter inconsidering of thermal conduction of LEDs is thermal resistance. Thesmaller the thermal resistance is, the better the thermal conduction is.Primarily, factors of thermal resistance include length of conductionpath, conduction area and thermal conductivity of a thermo-conductivematerial. It can be expressed by the following formula:

Thermal resistance=length of conduction path L/(conduction areaS*thermal conductivity)

That is to say, the shorter the conduction path is and the larger theconduction area is, the lower the thermal conductivity is.

As shown in FIG. 18, in this embodiment, the light board 3 includes atleast one LED chip set 31 having LED chips 311.

As shown in FIG. 18, in this embodiment, the light board 3 is dividedinto three areas comprising an inner ring, a middle ring and an outerring. All the LED chip sets 31 are located in the three areas. In oneexample, the inner ring, the middle ring and the outer ring areseparately mounted by different amount of LED chip sets 31. In anotheraspect, the light board 3 includes three LED chip sets 31. The three LEDchip sets 31 are respectively located in the inner ring, the middle ringand the outer ring. Each of the LED chip sets 31 separately in the innerring, the middle ring and the outer ring has at least one LED chip 311.

Four hypothetical circle lines are defined on the light board 3 as shownin FIG. 18. The outer ring is defined by the area between the outermosttwo circle lines of the four, the inner ring is defined by the areabetween the innermost two circle lines of the four, and the middle ringis located between the two areas mentioned above. In another embodiment,the light board 3 is separated into two rings (areas), and the chip sets31 are divided to be mounted on the two rings.

FIG. 20 is a schematic view of the combination of the fins 11 and theLED chips 311 of one embodiment. As shown in FIGS. 18 and 20, in thisembodiment, when at least one fin 11 is projected onto the plane onwhich the LED chip sets 31 are located along the axial direction of theLED lamp, a projection of the fin 11 at least touches at least one LEDchip 311 of the LED chip set 31. In detail, when at least one fin 11 isprojected onto a plane on which the LED chip set 31 is located along theaxial direction of the LED lamp, a projection of the fin 11 at leasttouches at least one LED chip 311 of the LED chip set 31 in the innerring, the middle ring or the outer ring. As shown in FIG. 20, theprojection of the fin 11 touches an LED chip 311. As indicated by thearrow in the figure, it is a heat dissipating path of the LED chip 311and the fin 11. As shown in FIG. 21, the projection of the fin 41 doesnot touch the LED chip 311 in the figure. As indicated by the arrow inthe figure, it is a heat dissipating path of the LED chip 311 and thefin 11. It can be seen that the heat dissipating path of the latter islonger than the former's. As a result, by means of a projection of a finat least touching at least one LED chip 311 of the LED chip set 31 inthe inner ring, the middle ring or the outer ring, a heat dissipatingpath of the LED chip 311 can be shortened. This can reduce thermalresistance to be advantageous to thermal conduction. Preferably, a fin11 is projected onto a plane on which the LED chip set 31 is locatedalong the axial direction of the LED lamp, a projection of any fin 11(the first fin 111 or the second fin 112) at least touches at least oneLED chip 311 of the LED chip set 31.

In this embodiment, the LED chip sets 31 in outer rings corresponding tothe fins 11 are greater than the LED chip sets 31 in inner rings innumber. Here the term “corresponding to” means projection relationshipin the axial direction of the LED lamp, for example, when the LED chipsets 31 in outer rings are projected onto the fins 11 in the axialdirection of the LED lamp, the fins 11 to which the LED chips 31 inouter rings correspond are located on a relatively outer portion of theheat sink 1. Here the LED chip sets 31 in outer rings have more LEDchips 311 in number, so they need more fins 11 (area) to implement heatdissipation.

As shown in FIGS. 1 and 18, the light board 3 has an inner border 3002and an outer border 3003. Both the inner border 3002 and the outerborder 3003 separately upward extend along the axial direction of theLED lamp to form a region. An area of part of the fins 11 inside theregion is greater than an area of part of the fins 11 outside theregion. As a result, the most of the fins 11 can correspond to the lightboard 3 (a shorter heat dissipating path) to enhance heat dissipatingefficiency of the fins 11 and increase effective area of heat conductionof the fins 11 to the LED chips 311.

As shown in FIGS. 3, 5 and 18, a reflecting region 3001 is disposed in aregion between the inner ring and an outer edge of the light board 3 toreflect the upward light to the light output surface 43. This can reduceloss of light in an opposite direction of light output in the axialdirection of the LED lamp to increase overall intensity of light output.

As shown in FIGS. 4 and 29, the light board 3 is formed with a thirdaperture 32 separately communicating with the first heat dissipatingchannel 7 a and the second heat dissipating channel 7 b. For example,the third aperture 32 communicates with spaces between the fins 11 andthe chamber of the lamp shell 2 to form air convection paths between thespaces between the fins 11 and between the chamber of the lamp shell 2and the outside of the Led lamp. The third aperture 32 is located insidethe inner ring of the LED lamp. Thus, it would not occupy the space ofthe reflecting region 3001 to affect reflective efficiency. In detail,the third aperture 32 is located at a central region of the light board3 and both the first air inlet 2201 and the second air inlet 1301 makeair intake through the same aperture (the third aperture 32). In oneexample, after convection air passes through the third aperture 32, andthen enters the first air inlet 2201 and the second air inlet 1301. Thethird aperture 32 is located at a central region of the light board 3,so both the first air inlet 2201 and the second air inlet 1301 cancommonly use the same air intake. Thus, this can prevent occupying anexcessive region of the light board 3 and prevent the usable regionalarea of the light board 3 for disposing the LED chips 311 fromdecreasing due to multiple air intakes. On the other hand, the sleeve 21corresponds to the third aperture 32, so convection air may have aneffect of thermal isolation to prevent temperatures inside and outsidethe sleeve 21 from mutually affecting each other when air enters. Inother embodiments, if both the first air inlet 2201 and the second airinlet 1301 are located at different positions, then the third aperture32 may be multiple in number to correspond to both the first air inlet2201 and the second air inlet 1301. In detail, as shown in FIG. 22, thethird aperture 32 may be located at a middle portion or outer portion orbetween the LED chips 311 to correspond to both the first air inlet 2201and the second air inlet 1301. stopped

FIG. 23 is a schematic view of the light board 3 in this embodiment. Asshown in FIG. 23, in this embodiment, the LED chip sets 31 are at leasttwo in number. The at least two LED chip sets 31 are annularly arrangedon the light board 3 in order. Each LED chip set 31 includes at leastone LED chip 311. Each LED chip 311 of one of the LED chip sets 31 onthe light board 3 is radially interlacedly arranged with any one LEDchip 311 of adjacent one of the LED chip sets 31 on the light board 3.That is, the LED chips 311 of different LED chip sets 31 are located indifferent directions in a radial direction of the LED lamp. In oneexample, if any line starting with the axis of the LED lamp andextending toward a radial direction of the LED lamp cuts two or more ofthe LED chips 311, then it will cut different positions of these two ormore LED chips 311 and will not cut the same positions of these two ormore LED chips 311. As a result, if there is convection on the lightboard 3 and air radially flows on the light board 3, the contact betweenair and the LED chips 311 will be more sufficient and a better effect ofheat dissipation will be obtained because of the airflow paths. Inaddition, in the aspect of lighting effect, such distribution of the LEDchips 311 is more advantageous to uniformity of light output.

FIGS. 24A-24C are perspective views of the power source 5 of oneembodiment at different viewpoints. FIG. 24D is a main view of the powersource 5 of one embodiment. The power source 5 is electrically connectedto the LED chips 311 to power the LED chips 311. As shown in FIGS.24A-24C, the power source 5 includes a power board 51 and a plurality ofelectronic components mounted thereon.

As shown in FIGS. 1, 2, 3 and 4, the lamp shell 2 includes the lamp head23, the lamp neck 22 and the sleeve 21. The lamp head 23 connects to thelamp neck 22 which connects to the sleeve 21. The sleeve 21 is locatedin the heat sink 1 (in the axial direction of the LED lamp, all or mostof the sleeve 21, for example, at least 80% of height of the sleeve 21,does not exceed the heat sink 1). The lamp neck 22 projects from theheat sink 1. Both the sleeve 21 and the lamp neck 22 can providesufficient space to receive the power source 5 and perform heatdissipation, especially for the power source 5 of a high power LED lamp(in comparison with a low power LED lamp, a power source of a high powerLED lamp has more complicated composition and larger size). The powersource 5 is received in both the lamp neck 22 and lamp head 23. Totalheight of the lamp neck 22 and the lamp head 23 is greater than heightof the heat sink 1 so as to provide more space for receiving the powersource 5. The heat sink 1 is separate from both the lamp neck 22 and thelamp head 23 (not overlap in the axial direction, the sleeve 21 isreceived in the heat sink 1). Thus, the power source 5 in both the lampneck 22 and the lamp head 23 is affected by the heat sink 1 slightly(heat of the heat sink 1 would not be conducted to the lamp neck 22 andthe lamp head 23 along a radial direction). In addition, theconfiguration of height of the lamp neck 22 is advantageous to thechimney effect of the first heat dissipating channel 7 a to guaranteeconvection efficiency of the first heat dissipating channel 7 a. Inother embodiments, height of the lamp neck 22 is at least 80% of heightof the heat sink 1 to accomplish the above function. The sleeve 21 ismade of a thermoisolated material to prevent mutual influence of heatfrom the fins and the power source.

As shown in FIG. 2, the second air inlet 1301 is located in a lowerportion of the heat sink 1 and radially corresponds to an inner side orthe inside of the heat sink 1, i.e. the second air inlet 1301 radiallycorresponds to the inner side or the inside of the fins 11. The innerside or the inside of the fins 11 corresponds to an outer wall (aradially inner side of the fins 11, which nears or abuts against thesleeve 21) of the sleeve 21 of the lamp shell 2. Thus, after convectionair flows into the second air inlet 1301, it flows upward along theouter wall of the sleeve 21 to perform convection and radiallydissipates heat in the inner side or the inside of the fins 11 and theouter wall of the sleeve 21 to implement an effect of thermal isolation.That is, this can prevent heat of the heat sink 1 is conducted from theouter wall of the sleeve 21 to the inside of the sleeve 21 not to affectthe power source 5. From the above, the second heat dissipating channel7 b can not only enhance heat dissipation of the fins 11, but alsoimplement an effect of thermal isolation. Make a positional comparisonbetween the second air inlet 1301 and the LED chips 311, the second airinlet 1301 is located radially inside all of the LED chips 311.

FIG. 25 is a cross-sectional view of the LED lamp of another embodiment.FIG. 26 is a schematic view of arrangement of the convection channels inthe LED lamp. As shown in FIGS. 25 and 26, in some embodiments, afundamental structure of the LED lamp is identical to the LED lamp shownin FIG. 1. In some embodiments, the sleeve 21 has an upper portion and alower portion. The upper portion is connected to the lower portionthrough an air guiding surface 216. A diameter of cross-section of theair guiding surface 216 downward tapers off along the axis of the LEDlamp (along the convection direction of the first heat dissipatingchannel 7 a). That is, the air guiding surface 216 can guide air in thesecond heat dissipating channel 7 b toward the radial outside of theheat sink 1 so as to make air be in contact with more area of the fins11 to bring out more heat of the fins 11. The sleeve 21 includes a firstportion and a second portion in the axial direction. The second portionis a part of the sleeve 21 below the air guiding surface 216 (includingthe air guiding surface 216). The first portion is the other part of thesleeve 21 above the air guiding surface 216 (but not including the airguiding surface 216). Electronic components of the power source 5, whichare located in the second portion of the sleeve 21, include heatintolerance elements such as capacitors, especially electrolyticcapacitors so as to make the heat intolerance elements work in lowtemperature environment (near the first air inlet 2201). In otherembodiments, high heat-generating elements may be disposed in the secondportion of the sleeve 21, such as resistors, inductors and transformers.As for the second heat dissipating channel 7 b, when convection airflows into the second heat dissipating channel 7 b and reaches the lowerportion of the sleeve 21, the convection air would lean against theouter wall of the sleeve 21 to rise. This can generate an effect ofthermal isolation, i.e. heat of the fins 11 is prevented from beingconducted to the inside of the sleeve 21 so that the heat intoleranceelements therein would not be affected. When the convection aircontinues to rise, the convection air will flow outward along radialdirections of the fins 11 under the guide of the air guiding surface 216so as to make the convection air be in contact with more area of thefins 11 to enhance an effect of heat dissipation of the fins 11. In thisembodiment, the inner chamber of the sleeve 21 is of awide-upper-side-and-narrow-lower-side channel structure. Thissignificantly enhances the chimney effect and promotes air flowing inthe sleeve 21. In addition, the venting hole 222 can be designed on thelamp neck 22 away from the vent to further improve the chimney effect.

The above depiction has been described with reference to theaccompanying drawings, in which exemplary embodiments of the disclosureare shown. This disclosure may, however, be embodied in many differentforms and should not be construed as limited to the embodiments setforth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art.

What is claimed is:
 1. An LED (light emitting diode) lamp comprising: alamp shell including a lamp head, a lamp neck and a sleeve, the lamphead connects to the lamp neck which connects to the sleeve; a passiveheat dissipating element having a heat sink connected to the lamp shell,wherein the heat sink comprises fins and a base, the sleeve of the lampshell is located in the heat sink, the lamp neck projects from the heatsink, height of the lamp neck is at least 80% of height of the heatsink; a power source having a first portion and a second portion,wherein the first portion of the power source is disposed in both thelamp neck and the lamp head of the lamp shell, and the second portion ofthe power source is disposed in the heat sink of the passive heatdissipating element; a light emitting surface connected to the heat sinkof the passive heat dissipating element and comprising LED chipselectrically connected to the power source, wherein the light emittingsurface and the heat sink are connected to form a heat transferring pathfrom the LED chips to the passive heat dissipating element; a first heatdissipating channel formed in a first chamber of the lamp shell fordissipating heat generated from the power source while the LED lamp isworking, and the first chamber is located between bottom of the LED lampand an upper portion of the lamp neck; a second heat dissipating channelformed in the heat sink and between the fins and the base of the heatsink for dissipating the heat generated from the LED chips andtransferred to the heat sink; and a lamp cover connected with the heatsink and having a light output surface and an end surface, wherein theend surface is formed with a vent to allow air flowing from outside ofthe LED lamp into both the first heat dissipating channel and the secondheat dissipating channel through the vent; wherein the first heatdissipating channel comprises a first end on the light emitting surfaceto allow air flowing from outside of the LED lamp into the firstchamber, and a second end on the upper portion of the lamp neck of thelamp shell to allow air flowing from inside of the first chamber out tothe LED lamp; wherein the second heat dissipating channel comprises athird end on the light emitting surface to allow air flowing fromoutside of the LED lamp into the second heat dissipating channel, andflowing out from spaces between every adjacent two of the fins; whereina third aperture is located in a central region of the light emittingsurface, and the third aperture forms an air intake of both the firstheat dissipating channel and the second heat dissipating channel;wherein the light emitting surface has an inner border and an outerborder encircling the inner border, both the inner border and the outerborder separately upward extend along an axial direction of the LED lampto form a region, an area of part of the fins inside the region isgreater than an area of part of the fins outside the region.
 2. The LEDlamp of claim 1, wherein the base of the heat sink has a lower endlocated under the base, the lower end protrudes from the light emittingsurface in an axis of the LED lamp; another side of the base of the heatsink, which is opposite to the lower end, has a back side, an end ofeach of the fins of the heat sink extends to connect with the back side,when the LED lamp is being hung, in an inward radial direction, the backside is upwardly slanted.
 3. The LED lamp of claim 2, wherein the finsinclude first fins and second fins, each of the first fins is dividedinto two portions in a radial direction of the LED lamp, the twoportions are divided with a gap portion, each of the second fins has athird portion and a fourth portion extending therefrom, the fourthportions are located radially outside the third portions, the thirdportion is connected to the fourth portion through a transition portion,the transition portion has a buffer section and a guide section, adirection of any tangent of the guide section is separate from the gapportion.
 4. The LED lamp of claim 3, wherein a receiving space isencompassed by the lower ends for receiving the lamp cover, height ofthe lamp cover received in the receiving space does not project from thelower end.
 5. The LED lamp of claim 4, wherein the light emittingsurface includes three LED chip sets, each of the three LED sets has LEDchips, the light emitting surface is divided into three areas comprisingan inner ring, a middle ring and an outer ring, the three LED chip setsare respectively located in the inner ring, the middle ring and theouter ring, when at least one fin of the heat sink is projected onto aplane on which the LED chip set is located along the axial direction ofthe LED lamp, a projection of the at least one fin at least touches atleast one LED chip of the LED chip set in the inner ring, the middlering or the outer ring.
 6. The LED lamp of claim 5, wherein any of thefins is projected onto a plane on which the LED chip set is locatedalong the axial direction of the LED lamp, a projection of any of thefins at least touches at least one LED chip of the LED chip set.
 7. TheLED lamp of claim 6, wherein the LED chip set in the outer ringcorresponding to the fins are greater than the LED chip set in the innerring in number, the LED chip set in the outer ring has more LED chipsthan the LED chip set in the inner ring in number.
 8. The LED lamp ofclaim 7, wherein the sleeve corresponds to the third aperture.
 9. TheLED lamp of claim 8, wherein each LED chip of one of the LED chip setson the light emitting surface is radially interlacedly arranged with anyone LED chip of adjacent one of the LED chip sets on the light emittingsurface.
 10. The LED lamp of claim 9, wherein the projecting area of thegap portion directly exactly corresponds to an area that the LED chipsare positioned on the light emitting surface.
 11. The LED lamp of claim10, wherein the first air inlet is projected onto the end surface in anaxis of the LED lamp to occupy an area on the end surface, which isdefined as a first portion, another area on the end surface is definedas a second portion, and the vent in the first portion is greater thanthe vent in the second portion in area.
 12. The LED lamp of claim 11,wherein an inner reflecting surface is disposed inside the light outputsurface of the lamp cover, an outer reflecting surface is disposed theouter circle of the array of LED chips.
 13. The LED lamp of claim 12,wherein a second chamber is formed between the light output surface, theinner reflecting surface, the outer reflecting surface and the lightemitting surface, the LED chips of the light emitting surface arelocated in the second chamber.
 14. The LED lamp of claim 13, wherein thesecond chamber has first apertures and second apertures, the firstapertures are configured to communicate with the outside, and the secondapertures are configured to communicate simultaneously with both thefirst heat dissipating channel and the second heat dissipating channel.15. The LED lamp of claim 14, wherein the light output surface isprovided with holes to form the first apertures, the first apertures areannularly located at a circumferential portion of the light outputsurface.
 16. The LED lamp of claim 15, wherein the inner reflectingsurface is provided with notches to form the second apertures, thesecond apertures are annularly located at a circumferential portion ofthe inner reflecting surface.
 17. The LED lamp of claim 16, wherein theratio of the number of the second apertures to that of the firstapertures is about 1:1-2.